Nowadays the electronic products on the market are becoming more and more powerful, operating at high speeds can produce a great amount of heat, but the conventional heat dissipating devices used for these products are usually aluminum extruding heat dissipating fins or with fans, which are more or less insufficient for these powerful electronic products. As a result, in the associated industries many manufacturers are continuously to develop new heat dissipating devices using new technologies such as heat pipes and vapor chambers, in which a type of vapor chambers which feature in fluid-vapor two-phase conversion have a widespread use as these vapor chambers provide a wide and flat surface contacting with the electronic products, allowing the heat generated by these electronic products to dissipate in a plane radiation way. In comparison with the unidirectional heat pipe heat dissipating devices, these vapor chamber heat dissipating devices are able to provide better heat dissipation by universal directions, lower heat resistance and higher heat conductivity.
As FIG. 1 shows, a recent vapor chamber usually consists of an upper cover 01, a lower cover 02 and a supporting element 03 disposed between the upper cover 01 and the lower cover 02, in production, all elements are placed between the covers before the covers are pressed. However this technique is rather difficult: if the wall of the covers is too thin, the covers will easily sink along with the supporting element 03; but if the wall of the covers is too thick, the weight of the vapor chamber produced will easily excess the design standard. Moreover, as usually a vapor chamber is quite large, the sides thereof are correspondingly long, therefor any small defects of pressing and welding in these sides may become the potentially risky spots in which the covers may split off in a high temperature. Thus, according to the descriptions above, it is obvious that the conventional manufacturing techniques of vapor chambers are complicated and difficult, consequently low in efficiency and high in manufacturing costs.
A basic configuration for a finished vapor chamber product comprises a cover with a vacuum chamber, in which a micro-structure is provided and filled by the working fluid; the heat conduction is realized by the heat absorption and dissipation of the working fluid in condensation and evaporation, and the capillary force generated by the micro structure on the working fluid. In addition, the vacuum in the cavity of the vapor chamber is required, the current producing technologies, whatever the chamber formed of a upper and a lower covers, or the chamber formed of a copper tube shaped, as shown in FIG. 2, all comprise several common steps: a step for powder filling and capillary structure sinter-forming, a step for supporting structure forming and chamber profiling, a step for sealing by argon welding or silver brazing and inserting a fine metal pipe as a fluid injection port, a step for injecting working fluid via the fluid injecting port, and a final step for chamber vacuuming and fluid injection port sealing.
However, the recent vapor chamber manufacturing method described above have the following shortcomings:
Firstly, the vapor chambers or semi-finished vapor chambers produced by foregoing steps all have a fine metal pipe welded in the fluid injection port as a reserved fluid injection pipe, which is shown as FIG. 3, in which 1 is a semi-finished vapor chamber, 101 is the sealing structure, 102 is the fluid injection pipe. The semi-finished vapor chamber with such a structure may be easily damaged because of accidental collision or pressure, consequently to cause higher rejection rate.
Furthermore, in the later manufacturing steps of working fluid injection, vacuum pumping, and sealing, the recent methods use an injector to inject the working fluid into the vapor chamber through the fine metal fluid injection pipe, and then remove the injector when the fluid injected achieves a certain volume, after that pass the semi-finished vapor chamber to another work station for vacuum pumping and sealing. This procedure is rather complicated, time consuming and has higher manufacturing cost.
In addition to above, because of the high vacuum in the cavity of the vapor chamber, the approach of using a same port for fluid injecting and vacuum pumping may result in a phenomenon of the rapid vaporization of the working fluid injected while the working fluid is being injected, which may lead to insufficient working fluid in the vapor chamber and consequently a so-called “dry out” phenomenon.